Abstract: In this paper, maintenance of blocking anticyclones are invested with four observed blocking anticyclones in different regions of Northern Hemisphere. It has been shown that there exists distinct region-dependent differences in the maintenance of time-mean quasi- strophic potential vorticity(PV) low in 300hPa within the bucking regions. In the two Pacifis blocking cases, the PV advection by time-mean flow tends to flow the low PV to north western part of the blocking highs and thus is benefit to the maintenance of the blockings' strength. The PV transfer by eddy tends to cancel the PV advection by mean flow. In the Atlantic and Asia blocking cases. however. the advection by mean flow tends to flow the low PV pattern eastward. The PV transfer by eddy has a tendency to advert low PV to western part of the ridges and to balance the advection by mean flow. Therefore. in these two cases it is the eddy that is benefit to the blockings'maintenance at quasi-stationary state. Very similar results are obtained with respect to maintenance of the time-mean Ertel PV in 330K surface. Therefore, in the blocking cases, the quasi-geostrophic PV analyses can be used to represent the Eretel PV analyses.